shields: lcd_par_s035: rename nxp_flexio_lcd to zephyr_mipi_dbi_parallel

Although the parallel mipi dbi mode pinout used for the LCD PAR S035
display is specific to NXP boards, the definition of the display is
generic, and does not require NXP-specific parallel mipi dbi IP.
Therefore, rename the MIPI DBI node for this display from
`nxp_flexio_lcd` to `zephyr_mipi_dbi_parallel`. The gpio-nexus node name
is unchanged, as the pinout it describes is specific to NXP.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>